"I assure adherents of other faiths that government will guarantee the security of their lives and property. I assure them that none of their rights will be trampled on," the governor was quoted as saying.

The forces driving this expansion are complex.

Some northern Nigerian politicians, dissatisfied with the government of President Olusegun Obasanjo, who is a Christian southerner, have used Sharia as a political tool.

But there is also a genuine popular enthusiasm for it, and some politicians have been swept along by this tide.